The 2005–06 Primeira Liga was the 72nd edition of top flight of Portuguese football. It started on 19 August 2005 with a match between Sporting CP and Belenenses and ended on 7 May 2006. The league was contested by 18 clubs with Benfica as defending champions.

The season's first goal was scored by Rogério, who scored a 39th-minute goal for Sporting against Belenenses. The first yellow card of the season was given to Sporting's Fábio Rochemback in the opening game of the season, and the first red card was given to Benfica's João Pereira in his club's away draw against Académica de Coimbra.